drivers/net/pppol2tp.c

   1 /*****************************************************************************
   2  * Linux PPP over L2TP (PPPoX/PPPoL2TP) Sockets
   3  *
   4  * PPPoX    --- Generic PPP encapsulation socket family
   5  * PPPoL2TP --- PPP over L2TP (RFC 2661)
   6  *
   7  * Version:     1.0.0
   8  *
   9  * Authors:     Martijn van Oosterhout <kleptog@svana.org>
  10  *              James Chapman (jchapman@katalix.com)
  11  * Contributors:
  12  *              Michal Ostrowski <mostrows@speakeasy.net>
  13  *              Arnaldo Carvalho de Melo <acme@xconectiva.com.br>
  14  *              David S. Miller (davem@redhat.com)
  15  *
  16  * License:
  17  *              This program is free software; you can redistribute it and/or
  18  *              modify it under the terms of the GNU General Public License
  19  *              as published by the Free Software Foundation; either version
  20  *              2 of the License, or (at your option) any later version.
  21  *
  22  */
  23
  24 /* This driver handles only L2TP data frames; control frames are handled by a
  25  * userspace application.
  26  *
  27  * To send data in an L2TP session, userspace opens a PPPoL2TP socket and
  28  * attaches it to a bound UDP socket with local tunnel_id / session_id and
  29  * peer tunnel_id / session_id set. Data can then be sent or received using
  30  * regular socket sendmsg() / recvmsg() calls. Kernel parameters of the socket
  31  * can be read or modified using ioctl() or [gs]etsockopt() calls.
  32  *
  33  * When a PPPoL2TP socket is connected with local and peer session_id values
  34  * zero, the socket is treated as a special tunnel management socket.
  35  *
  36  * Here's example userspace code to create a socket for sending/receiving data
  37  * over an L2TP session:-
  38  *
  39  *      struct sockaddr_pppol2tp sax;
  40  *      int fd;
  41  *      int session_fd;
  42  *
  43  *      fd = socket(AF_PPPOX, SOCK_DGRAM, PX_PROTO_OL2TP);
  44  *
  45  *      sax.sa_family = AF_PPPOX;
  46  *      sax.sa_protocol = PX_PROTO_OL2TP;
  47  *      sax.pppol2tp.fd = tunnel_fd;    // bound UDP socket
  48  *      sax.pppol2tp.addr.sin_addr.s_addr = addr->sin_addr.s_addr;
  49  *      sax.pppol2tp.addr.sin_port = addr->sin_port;
  50  *      sax.pppol2tp.addr.sin_family = AF_INET;
  51  *      sax.pppol2tp.s_tunnel  = tunnel_id;
  52  *      sax.pppol2tp.s_session = session_id;
  53  *      sax.pppol2tp.d_tunnel  = peer_tunnel_id;
  54  *      sax.pppol2tp.d_session = peer_session_id;
  55  *
  56  *      session_fd = connect(fd, (struct sockaddr *)&sax, sizeof(sax));
  57  *
  58  * A pppd plugin that allows PPP traffic to be carried over L2TP using
  59  * this driver is available from the OpenL2TP project at
  60  * http://openl2tp.sourceforge.net.
  61  */
  62
  63 #include <linux/module.h>
  64 #include <linux/string.h>
  65 #include <linux/list.h>
  66 #include <asm/uaccess.h>
  67
  68 #include <linux/kernel.h>
  69 #include <linux/spinlock.h>
  70 #include <linux/kthread.h>
  71 #include <linux/sched.h>
  72 #include <linux/slab.h>
  73 #include <linux/errno.h>
  74 #include <linux/jiffies.h>
  75
  76 #include <linux/netdevice.h>
  77 #include <linux/net.h>
  78 #include <linux/inetdevice.h>
  79 #include <linux/skbuff.h>
  80 #include <linux/init.h>
  81 #include <linux/ip.h>
  82 #include <linux/udp.h>
  83 #include <linux/if_pppox.h>
  84 #include <linux/if_pppol2tp.h>
  85 #include <net/sock.h>
  86 #include <linux/ppp_channel.h>
  87 #include <linux/ppp_defs.h>
  88 #include <linux/if_ppp.h>
  89 #include <linux/file.h>
  90 #include <linux/hash.h>
  91 #include <linux/sort.h>
  92 #include <linux/proc_fs.h>
  93 #include <linux/nsproxy.h>
  94 #include <net/net_namespace.h>
  95 #include <net/netns/generic.h>
  96 #include <net/dst.h>
  97 #include <net/ip.h>
  98 #include <net/udp.h>
  99 #include <net/xfrm.h>
 100
 101 #include <asm/byteorder.h>
 102 #include <asm/atomic.h>
 103
 104
 105 #define PPPOL2TP_DRV_VERSION    "V1.0"
 106
 107 /* L2TP header constants */
 108 #define L2TP_HDRFLAG_T     0x8000
 109 #define L2TP_HDRFLAG_L     0x4000
 110 #define L2TP_HDRFLAG_S     0x0800
 111 #define L2TP_HDRFLAG_O     0x0200
 112 #define L2TP_HDRFLAG_P     0x0100
 113
 114 #define L2TP_HDR_VER_MASK  0x000F
 115 #define L2TP_HDR_VER       0x0002
 116
 117 /* Space for UDP, L2TP and PPP headers */
 118 #define PPPOL2TP_HEADER_OVERHEAD        40
 119
 120 /* Just some random numbers */
 121 #define L2TP_TUNNEL_MAGIC       0x42114DDA
 122 #define L2TP_SESSION_MAGIC      0x0C04EB7D
 123
 124 #define PPPOL2TP_HASH_BITS      4
 125 #define PPPOL2TP_HASH_SIZE      (1 << PPPOL2TP_HASH_BITS)
 126
 127 /* Default trace flags */
 128 #define PPPOL2TP_DEFAULT_DEBUG_FLAGS    0
 129
 130 #define PRINTK(_mask, _type, _lvl, _fmt, args...)                       \
 131         do {                                                            \
 132                 if ((_mask) & (_type))                                  \
 133                         printk(_lvl "PPPOL2TP: " _fmt, ##args);         \
 134         } while(0)
 135
 136 /* Number of bytes to build transmit L2TP headers.
 137  * Unfortunately the size is different depending on whether sequence numbers
 138  * are enabled.
 139  */
 140 #define PPPOL2TP_L2TP_HDR_SIZE_SEQ              10
 141 #define PPPOL2TP_L2TP_HDR_SIZE_NOSEQ            6
 142
 143 struct pppol2tp_tunnel;
 144
 145 /* Describes a session. It is the sk_user_data field in the PPPoL2TP
 146  * socket. Contains information to determine incoming packets and transmit
 147  * outgoing ones.
 148  */
 149 struct pppol2tp_session
 150 {
 151         int                     magic;          /* should be
 152                                                  * L2TP_SESSION_MAGIC */
 153         int                     owner;          /* pid that opened the socket */
 154
 155         struct sock             *sock;          /* Pointer to the session
 156                                                  * PPPoX socket */
 157         struct sock             *tunnel_sock;   /* Pointer to the tunnel UDP
 158                                                  * socket */
 159
 160         struct pppol2tp_addr    tunnel_addr;    /* Description of tunnel */
 161
 162         struct pppol2tp_tunnel  *tunnel;        /* back pointer to tunnel
 163                                                  * context */
 164
 165         char                    name[20];       /* "sess xxxxx/yyyyy", where
 166                                                  * x=tunnel_id, y=session_id */
 167         int                     mtu;
 168         int                     mru;
 169         int                     flags;          /* accessed by PPPIOCGFLAGS.
 170                                                  * Unused. */
 171         unsigned                recv_seq:1;     /* expect receive packets with
 172                                                  * sequence numbers? */
 173         unsigned                send_seq:1;     /* send packets with sequence
 174                                                  * numbers? */
 175         unsigned                lns_mode:1;     /* behave as LNS? LAC enables
 176                                                  * sequence numbers under
 177                                                  * control of LNS. */
 178         int                     debug;          /* bitmask of debug message
 179                                                  * categories */
 180         int                     reorder_timeout; /* configured reorder timeout
 181                                                   * (in jiffies) */
 182         u16                     nr;             /* session NR state (receive) */
 183         u16                     ns;             /* session NR state (send) */
 184         struct sk_buff_head     reorder_q;      /* receive reorder queue */
 185         struct pppol2tp_ioc_stats stats;
 186         struct hlist_node       hlist;          /* Hash list node */
 187 };
 188
 189 /* The sk_user_data field of the tunnel's UDP socket. It contains info to track
 190  * all the associated sessions so incoming packets can be sorted out
 191  */
 192 struct pppol2tp_tunnel
 193 {
 194         int                     magic;          /* Should be L2TP_TUNNEL_MAGIC */
 195         rwlock_t                hlist_lock;     /* protect session_hlist */
 196         struct hlist_head       session_hlist[PPPOL2TP_HASH_SIZE];
 197                                                 /* hashed list of sessions,
 198                                                  * hashed by id */
 199         int                     debug;          /* bitmask of debug message
 200                                                  * categories */
 201         char                    name[12];       /* "tunl xxxxx" */
 202         struct pppol2tp_ioc_stats stats;
 203
 204         void (*old_sk_destruct)(struct sock *);
 205
 206         struct sock             *sock;          /* Parent socket */
 207         struct list_head        list;           /* Keep a list of all open
 208                                                  * prepared sockets */
 209         struct net              *pppol2tp_net;  /* the net we belong to */
 210
 211         atomic_t                ref_count;
 212 };
 213
 214 /* Private data stored for received packets in the skb.
 215  */
 216 struct pppol2tp_skb_cb {
 217         u16                     ns;
 218         u16                     nr;
 219         u16                     has_seq;
 220         u16                     length;
 221         unsigned long           expires;
 222 };
 223
 224 #define PPPOL2TP_SKB_CB(skb)    ((struct pppol2tp_skb_cb *) &skb->cb[sizeof(struct inet_skb_parm)])
 225
 226 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb);
 227 static void pppol2tp_tunnel_free(struct pppol2tp_tunnel *tunnel);
 228
 229 static atomic_t pppol2tp_tunnel_count;
 230 static atomic_t pppol2tp_session_count;
 231 static struct ppp_channel_ops pppol2tp_chan_ops = { pppol2tp_xmit , NULL };
 232 static struct proto_ops pppol2tp_ops;
 233
 234 /* per-net private data for this module */
 235 static int pppol2tp_net_id;
 236 struct pppol2tp_net {
 237         struct list_head pppol2tp_tunnel_list;
 238         rwlock_t pppol2tp_tunnel_list_lock;
 239 };
 240
 241 static inline struct pppol2tp_net *pppol2tp_pernet(struct net *net)
 242 {
 243         BUG_ON(!net);
 244
 245         return net_generic(net, pppol2tp_net_id);
 246 }
 247
 248 /* Helpers to obtain tunnel/session contexts from sockets.
 249  */
 250 static inline struct pppol2tp_session *pppol2tp_sock_to_session(struct sock *sk)
 251 {
 252         struct pppol2tp_session *session;
 253
 254         if (sk == NULL)
 255                 return NULL;
 256
 257         sock_hold(sk);
 258         session = (struct pppol2tp_session *)(sk->sk_user_data);
 259         if (session == NULL) {
 260                 sock_put(sk);
 261                 goto out;
 262         }
 263
 264         BUG_ON(session->magic != L2TP_SESSION_MAGIC);
 265 out:
 266         return session;
 267 }
 268
 269 static inline struct pppol2tp_tunnel *pppol2tp_sock_to_tunnel(struct sock *sk)
 270 {
 271         struct pppol2tp_tunnel *tunnel;
 272
 273         if (sk == NULL)
 274                 return NULL;
 275
 276         sock_hold(sk);
 277         tunnel = (struct pppol2tp_tunnel *)(sk->sk_user_data);
 278         if (tunnel == NULL) {
 279                 sock_put(sk);
 280                 goto out;
 281         }
 282
 283         BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
 284 out:
 285         return tunnel;
 286 }
 287
 288 /* Tunnel reference counts. Incremented per session that is added to
 289  * the tunnel.
 290  */
 291 static inline void pppol2tp_tunnel_inc_refcount(struct pppol2tp_tunnel *tunnel)
 292 {
 293         atomic_inc(&tunnel->ref_count);
 294 }
 295
 296 static inline void pppol2tp_tunnel_dec_refcount(struct pppol2tp_tunnel *tunnel)
 297 {
 298         if (atomic_dec_and_test(&tunnel->ref_count))
 299                 pppol2tp_tunnel_free(tunnel);
 300 }
 301
 302 /* Session hash list.
 303  * The session_id SHOULD be random according to RFC2661, but several
 304  * L2TP implementations (Cisco and Microsoft) use incrementing
 305  * session_ids.  So we do a real hash on the session_id, rather than a
 306  * simple bitmask.
 307  */
 308 static inline struct hlist_head *
 309 pppol2tp_session_id_hash(struct pppol2tp_tunnel *tunnel, u16 session_id)
 310 {
 311         unsigned long hash_val = (unsigned long) session_id;
 312         return &tunnel->session_hlist[hash_long(hash_val, PPPOL2TP_HASH_BITS)];
 313 }
 314
 315 /* Lookup a session by id
 316  */
 317 static struct pppol2tp_session *
 318 pppol2tp_session_find(struct pppol2tp_tunnel *tunnel, u16 session_id)
 319 {
 320         struct hlist_head *session_list =
 321                 pppol2tp_session_id_hash(tunnel, session_id);
 322         struct pppol2tp_session *session;
 323         struct hlist_node *walk;
 324
 325         read_lock_bh(&tunnel->hlist_lock);
 326         hlist_for_each_entry(session, walk, session_list, hlist) {
 327                 if (session->tunnel_addr.s_session == session_id) {
 328                         read_unlock_bh(&tunnel->hlist_lock);
 329                         return session;
 330                 }
 331         }
 332         read_unlock_bh(&tunnel->hlist_lock);
 333
 334         return NULL;
 335 }
 336
 337 /* Lookup a tunnel by id
 338  */
 339 static struct pppol2tp_tunnel *pppol2tp_tunnel_find(struct net *net, u16 tunnel_id)
 340 {
 341         struct pppol2tp_tunnel *tunnel;
 342         struct pppol2tp_net *pn = pppol2tp_pernet(net);
 343
 344         read_lock_bh(&pn->pppol2tp_tunnel_list_lock);
 345         list_for_each_entry(tunnel, &pn->pppol2tp_tunnel_list, list) {
 346                 if (tunnel->stats.tunnel_id == tunnel_id) {
 347                         read_unlock_bh(&pn->pppol2tp_tunnel_list_lock);
 348                         return tunnel;
 349                 }
 350         }
 351         read_unlock_bh(&pn->pppol2tp_tunnel_list_lock);
 352
 353         return NULL;
 354 }
 355
 356 /*****************************************************************************
 357  * Receive data handling
 358  *****************************************************************************/
 359
 360 /* Queue a skb in order. We come here only if the skb has an L2TP sequence
 361  * number.
 362  */
 363 static void pppol2tp_recv_queue_skb(struct pppol2tp_session *session, struct sk_buff *skb)
 364 {
 365         struct sk_buff *skbp;
 366         struct sk_buff *tmp;
 367         u16 ns = PPPOL2TP_SKB_CB(skb)->ns;
 368
 369         spin_lock_bh(&session->reorder_q.lock);
 370         skb_queue_walk_safe(&session->reorder_q, skbp, tmp) {
 371                 if (PPPOL2TP_SKB_CB(skbp)->ns > ns) {
 372                         __skb_queue_before(&session->reorder_q, skbp, skb);
 373                         PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 374                                "%s: pkt %hu, inserted before %hu, reorder_q len=%d\n",
 375                                session->name, ns, PPPOL2TP_SKB_CB(skbp)->ns,
 376                                skb_queue_len(&session->reorder_q));
 377                         session->stats.rx_oos_packets++;
 378                         goto out;
 379                 }
 380         }
 381
 382         __skb_queue_tail(&session->reorder_q, skb);
 383
 384 out:
 385         spin_unlock_bh(&session->reorder_q.lock);
 386 }
 387
 388 /* Dequeue a single skb.
 389  */
 390 static void pppol2tp_recv_dequeue_skb(struct pppol2tp_session *session, struct sk_buff *skb)
 391 {
 392         struct pppol2tp_tunnel *tunnel = session->tunnel;
 393         int length = PPPOL2TP_SKB_CB(skb)->length;
 394         struct sock *session_sock = NULL;
 395
 396         /* We're about to requeue the skb, so return resources
 397          * to its current owner (a socket receive buffer).
 398          */
 399         skb_orphan(skb);
 400
 401         tunnel->stats.rx_packets++;
 402         tunnel->stats.rx_bytes += length;
 403         session->stats.rx_packets++;
 404         session->stats.rx_bytes += length;
 405
 406         if (PPPOL2TP_SKB_CB(skb)->has_seq) {
 407                 /* Bump our Nr */
 408                 session->nr++;
 409                 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 410                        "%s: updated nr to %hu\n", session->name, session->nr);
 411         }
 412
 413         /* If the socket is bound, send it in to PPP's input queue. Otherwise
 414          * queue it on the session socket.
 415          */
 416         session_sock = session->sock;
 417         if (session_sock->sk_state & PPPOX_BOUND) {
 418                 struct pppox_sock *po;
 419                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
 420                        "%s: recv %d byte data frame, passing to ppp\n",
 421                        session->name, length);
 422
 423                 /* We need to forget all info related to the L2TP packet
 424                  * gathered in the skb as we are going to reuse the same
 425                  * skb for the inner packet.
 426                  * Namely we need to:
 427                  * - reset xfrm (IPSec) information as it applies to
 428                  *   the outer L2TP packet and not to the inner one
 429                  * - release the dst to force a route lookup on the inner
 430                  *   IP packet since skb->dst currently points to the dst
 431                  *   of the UDP tunnel
 432                  * - reset netfilter information as it doesn't apply
 433                  *   to the inner packet either
 434                  */
 435                 secpath_reset(skb);
 436                 dst_release(skb->dst);
 437                 skb->dst = NULL;
 438                 nf_reset(skb);
 439
 440                 po = pppox_sk(session_sock);
 441                 ppp_input(&po->chan, skb);
 442         } else {
 443                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_INFO,
 444                        "%s: socket not bound\n", session->name);
 445
 446                 /* Not bound. Nothing we can do, so discard. */
 447                 session->stats.rx_errors++;
 448                 kfree_skb(skb);
 449         }
 450
 451         sock_put(session->sock);
 452 }
 453
 454 /* Dequeue skbs from the session's reorder_q, subject to packet order.
 455  * Skbs that have been in the queue for too long are simply discarded.
 456  */
 457 static void pppol2tp_recv_dequeue(struct pppol2tp_session *session)
 458 {
 459         struct sk_buff *skb;
 460         struct sk_buff *tmp;
 461
 462         /* If the pkt at the head of the queue has the nr that we
 463          * expect to send up next, dequeue it and any other
 464          * in-sequence packets behind it.
 465          */
 466         spin_lock_bh(&session->reorder_q.lock);
 467         skb_queue_walk_safe(&session->reorder_q, skb, tmp) {
 468                 if (time_after(jiffies, PPPOL2TP_SKB_CB(skb)->expires)) {
 469                         session->stats.rx_seq_discards++;
 470                         session->stats.rx_errors++;
 471                         PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 472                                "%s: oos pkt %hu len %d discarded (too old), "
 473                                "waiting for %hu, reorder_q_len=%d\n",
 474                                session->name, PPPOL2TP_SKB_CB(skb)->ns,
 475                                PPPOL2TP_SKB_CB(skb)->length, session->nr,
 476                                skb_queue_len(&session->reorder_q));
 477                         __skb_unlink(skb, &session->reorder_q);
 478                         kfree_skb(skb);
 479                         sock_put(session->sock);
 480                         continue;
 481                 }
 482
 483                 if (PPPOL2TP_SKB_CB(skb)->has_seq) {
 484                         if (PPPOL2TP_SKB_CB(skb)->ns != session->nr) {
 485                                 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 486                                        "%s: holding oos pkt %hu len %d, "
 487                                        "waiting for %hu, reorder_q_len=%d\n",
 488                                        session->name, PPPOL2TP_SKB_CB(skb)->ns,
 489                                        PPPOL2TP_SKB_CB(skb)->length, session->nr,
 490                                        skb_queue_len(&session->reorder_q));
 491                                 goto out;
 492                         }
 493                 }
 494                 __skb_unlink(skb, &session->reorder_q);
 495
 496                 /* Process the skb. We release the queue lock while we
 497                  * do so to let other contexts process the queue.
 498                  */
 499                 spin_unlock_bh(&session->reorder_q.lock);
 500                 pppol2tp_recv_dequeue_skb(session, skb);
 501                 spin_lock_bh(&session->reorder_q.lock);
 502         }
 503
 504 out:
 505         spin_unlock_bh(&session->reorder_q.lock);
 506 }
 507
 508 static inline int pppol2tp_verify_udp_checksum(struct sock *sk,
 509                                                struct sk_buff *skb)
 510 {
 511         struct udphdr *uh = udp_hdr(skb);
 512         u16 ulen = ntohs(uh->len);
 513         struct inet_sock *inet;
 514         __wsum psum;
 515
 516         if (sk->sk_no_check || skb_csum_unnecessary(skb) || !uh->check)
 517                 return 0;
 518
 519         inet = inet_sk(sk);
 520         psum = csum_tcpudp_nofold(inet->saddr, inet->daddr, ulen,
 521                                   IPPROTO_UDP, 0);
 522
 523         if ((skb->ip_summed == CHECKSUM_COMPLETE) &&
 524             !csum_fold(csum_add(psum, skb->csum)))
 525                 return 0;
 526
 527         skb->csum = psum;
 528
 529         return __skb_checksum_complete(skb);
 530 }
 531
 532 /* Internal receive frame. Do the real work of receiving an L2TP data frame
 533  * here. The skb is not on a list when we get here.
 534  * Returns 0 if the packet was a data packet and was successfully passed on.
 535  * Returns 1 if the packet was not a good data packet and could not be
 536  * forwarded.  All such packets are passed up to userspace to deal with.
 537  */
 538 static int pppol2tp_recv_core(struct sock *sock, struct sk_buff *skb)
 539 {
 540         struct pppol2tp_session *session = NULL;
 541         struct pppol2tp_tunnel *tunnel;
 542         unsigned char *ptr, *optr;
 543         u16 hdrflags;
 544         u16 tunnel_id, session_id;
 545         int length;
 546         int offset;
 547
 548         tunnel = pppol2tp_sock_to_tunnel(sock);
 549         if (tunnel == NULL)
 550                 goto no_tunnel;
 551
 552         if (tunnel->sock && pppol2tp_verify_udp_checksum(tunnel->sock, skb))
 553                 goto discard_bad_csum;
 554
 555         /* UDP always verifies the packet length. */
 556         __skb_pull(skb, sizeof(struct udphdr));
 557
 558         /* Short packet? */
 559         if (!pskb_may_pull(skb, 12)) {
 560                 PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_INFO,
 561                        "%s: recv short packet (len=%d)\n", tunnel->name, skb->len);
 562                 goto error;
 563         }
 564
 565         /* Point to L2TP header */
 566         optr = ptr = skb->data;
 567
 568         /* Get L2TP header flags */
 569         hdrflags = ntohs(*(__be16*)ptr);
 570
 571         /* Trace packet contents, if enabled */
 572         if (tunnel->debug & PPPOL2TP_MSG_DATA) {
 573                 length = min(16u, skb->len);
 574                 if (!pskb_may_pull(skb, length))
 575                         goto error;
 576
 577                 printk(KERN_DEBUG "%s: recv: ", tunnel->name);
 578
 579                 offset = 0;
 580                 do {
 581                         printk(" %02X", ptr[offset]);
 582                 } while (++offset < length);
 583
 584                 printk("\n");
 585         }
 586
 587         /* Get length of L2TP packet */
 588         length = skb->len;
 589
 590         /* If type is control packet, it is handled by userspace. */
 591         if (hdrflags & L2TP_HDRFLAG_T) {
 592                 PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
 593                        "%s: recv control packet, len=%d\n", tunnel->name, length);
 594                 goto error;
 595         }
 596
 597         /* Skip flags */
 598         ptr += 2;
 599
 600         /* If length is present, skip it */
 601         if (hdrflags & L2TP_HDRFLAG_L)
 602                 ptr += 2;
 603
 604         /* Extract tunnel and session ID */
 605         tunnel_id = ntohs(*(__be16 *) ptr);
 606         ptr += 2;
 607         session_id = ntohs(*(__be16 *) ptr);
 608         ptr += 2;
 609
 610         /* Find the session context */
 611         session = pppol2tp_session_find(tunnel, session_id);
 612         if (!session) {
 613                 /* Not found? Pass to userspace to deal with */
 614                 PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_INFO,
 615                        "%s: no socket found (%hu/%hu). Passing up.\n",
 616                        tunnel->name, tunnel_id, session_id);
 617                 goto error;
 618         }
 619         sock_hold(session->sock);
 620
 621         /* The ref count on the socket was increased by the above call since
 622          * we now hold a pointer to the session. Take care to do sock_put()
 623          * when exiting this function from now on...
 624          */
 625
 626         /* Handle the optional sequence numbers.  If we are the LAC,
 627          * enable/disable sequence numbers under the control of the LNS.  If
 628          * no sequence numbers present but we were expecting them, discard
 629          * frame.
 630          */
 631         if (hdrflags & L2TP_HDRFLAG_S) {
 632                 u16 ns, nr;
 633                 ns = ntohs(*(__be16 *) ptr);
 634                 ptr += 2;
 635                 nr = ntohs(*(__be16 *) ptr);
 636                 ptr += 2;
 637
 638                 /* Received a packet with sequence numbers. If we're the LNS,
 639                  * check if we sre sending sequence numbers and if not,
 640                  * configure it so.
 641                  */
 642                 if ((!session->lns_mode) && (!session->send_seq)) {
 643                         PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_INFO,
 644                                "%s: requested to enable seq numbers by LNS\n",
 645                                session->name);
 646                         session->send_seq = -1;
 647                 }
 648
 649                 /* Store L2TP info in the skb */
 650                 PPPOL2TP_SKB_CB(skb)->ns = ns;
 651                 PPPOL2TP_SKB_CB(skb)->nr = nr;
 652                 PPPOL2TP_SKB_CB(skb)->has_seq = 1;
 653
 654                 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 655                        "%s: recv data ns=%hu, nr=%hu, session nr=%hu\n",
 656                        session->name, ns, nr, session->nr);
 657         } else {
 658                 /* No sequence numbers.
 659                  * If user has configured mandatory sequence numbers, discard.
 660                  */
 661                 if (session->recv_seq) {
 662                         PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_WARNING,
 663                                "%s: recv data has no seq numbers when required. "
 664                                "Discarding\n", session->name);
 665                         session->stats.rx_seq_discards++;
 666                         goto discard;
 667                 }
 668
 669                 /* If we're the LAC and we're sending sequence numbers, the
 670                  * LNS has requested that we no longer send sequence numbers.
 671                  * If we're the LNS and we're sending sequence numbers, the
 672                  * LAC is broken. Discard the frame.
 673                  */
 674                 if ((!session->lns_mode) && (session->send_seq)) {
 675                         PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_INFO,
 676                                "%s: requested to disable seq numbers by LNS\n",
 677                                session->name);
 678                         session->send_seq = 0;
 679                 } else if (session->send_seq) {
 680                         PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_WARNING,
 681                                "%s: recv data has no seq numbers when required. "
 682                                "Discarding\n", session->name);
 683                         session->stats.rx_seq_discards++;
 684                         goto discard;
 685                 }
 686
 687                 /* Store L2TP info in the skb */
 688                 PPPOL2TP_SKB_CB(skb)->has_seq = 0;
 689         }
 690
 691         /* If offset bit set, skip it. */
 692         if (hdrflags & L2TP_HDRFLAG_O) {
 693                 offset = ntohs(*(__be16 *)ptr);
 694                 ptr += 2 + offset;
 695         }
 696
 697         offset = ptr - optr;
 698         if (!pskb_may_pull(skb, offset))
 699                 goto discard;
 700
 701         __skb_pull(skb, offset);
 702
 703         /* Skip PPP header, if present.  In testing, Microsoft L2TP clients
 704          * don't send the PPP header (PPP header compression enabled), but
 705          * other clients can include the header. So we cope with both cases
 706          * here. The PPP header is always FF03 when using L2TP.
 707          *
 708          * Note that skb->data[] isn't dereferenced from a u16 ptr here since
 709          * the field may be unaligned.
 710          */
 711         if (!pskb_may_pull(skb, 2))
 712                 goto discard;
 713
 714         if ((skb->data[0] == 0xff) && (skb->data[1] == 0x03))
 715                 skb_pull(skb, 2);
 716
 717         /* Prepare skb for adding to the session's reorder_q.  Hold
 718          * packets for max reorder_timeout or 1 second if not
 719          * reordering.
 720          */
 721         PPPOL2TP_SKB_CB(skb)->length = length;
 722         PPPOL2TP_SKB_CB(skb)->expires = jiffies +
 723                 (session->reorder_timeout ? session->reorder_timeout : HZ);
 724
 725         /* Add packet to the session's receive queue. Reordering is done here, if
 726          * enabled. Saved L2TP protocol info is stored in skb->sb[].
 727          */
 728         if (PPPOL2TP_SKB_CB(skb)->has_seq) {
 729                 if (session->reorder_timeout != 0) {
 730                         /* Packet reordering enabled. Add skb to session's
 731                          * reorder queue, in order of ns.
 732                          */
 733                         pppol2tp_recv_queue_skb(session, skb);
 734                 } else {
 735                         /* Packet reordering disabled. Discard out-of-sequence
 736                          * packets
 737                          */
 738                         if (PPPOL2TP_SKB_CB(skb)->ns != session->nr) {
 739                                 session->stats.rx_seq_discards++;
 740                                 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 741                                        "%s: oos pkt %hu len %d discarded, "
 742                                        "waiting for %hu, reorder_q_len=%d\n",
 743                                        session->name, PPPOL2TP_SKB_CB(skb)->ns,
 744                                        PPPOL2TP_SKB_CB(skb)->length, session->nr,
 745                                        skb_queue_len(&session->reorder_q));
 746                                 goto discard;
 747                         }
 748                         skb_queue_tail(&session->reorder_q, skb);
 749                 }
 750         } else {
 751                 /* No sequence numbers. Add the skb to the tail of the
 752                  * reorder queue. This ensures that it will be
 753                  * delivered after all previous sequenced skbs.
 754                  */
 755                 skb_queue_tail(&session->reorder_q, skb);
 756         }
 757
 758         /* Try to dequeue as many skbs from reorder_q as we can. */
 759         pppol2tp_recv_dequeue(session);
 760
 761         return 0;
 762
 763 discard:
 764         session->stats.rx_errors++;
 765         kfree_skb(skb);
 766         sock_put(session->sock);
 767         sock_put(sock);
 768
 769         return 0;
 770
 771 discard_bad_csum:
 772         LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name);
 773         UDP_INC_STATS_USER(&init_net, UDP_MIB_INERRORS, 0);
 774         tunnel->stats.rx_errors++;
 775         kfree_skb(skb);
 776
 777         return 0;
 778
 779 error:
 780         /* Put UDP header back */
 781         __skb_push(skb, sizeof(struct udphdr));
 782         sock_put(sock);
 783
 784 no_tunnel:
 785         return 1;
 786 }
 787
 788 /* UDP encapsulation receive handler. See net/ipv4/udp.c.
 789  * Return codes:
 790  * 0 : success.
 791  * <0: error
 792  * >0: skb should be passed up to userspace as UDP.
 793  */
 794 static int pppol2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
 795 {
 796         struct pppol2tp_tunnel *tunnel;
 797
 798         tunnel = pppol2tp_sock_to_tunnel(sk);
 799         if (tunnel == NULL)
 800                 goto pass_up;
 801
 802         PRINTK(tunnel->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
 803                "%s: received %d bytes\n", tunnel->name, skb->len);
 804
 805         if (pppol2tp_recv_core(sk, skb))
 806                 goto pass_up_put;
 807
 808         sock_put(sk);
 809         return 0;
 810
 811 pass_up_put:
 812         sock_put(sk);
 813 pass_up:
 814         return 1;
 815 }
 816
 817 /* Receive message. This is the recvmsg for the PPPoL2TP socket.
 818  */
 819 static int pppol2tp_recvmsg(struct kiocb *iocb, struct socket *sock,
 820                             struct msghdr *msg, size_t len,
 821                             int flags)
 822 {
 823         int err;
 824         struct sk_buff *skb;
 825         struct sock *sk = sock->sk;
 826
 827         err = -EIO;
 828         if (sk->sk_state & PPPOX_BOUND)
 829                 goto end;
 830
 831         msg->msg_namelen = 0;
 832
 833         err = 0;
 834         skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
 835                                 flags & MSG_DONTWAIT, &err);
 836         if (!skb)
 837                 goto end;
 838
 839         if (len > skb->len)
 840                 len = skb->len;
 841         else if (len < skb->len)
 842                 msg->msg_flags |= MSG_TRUNC;
 843
 844         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, len);
 845         if (likely(err == 0))
 846                 err = len;
 847
 848         kfree_skb(skb);
 849 end:
 850         return err;
 851 }
 852
 853 /************************************************************************
 854  * Transmit handling
 855  ***********************************************************************/
 856
 857 /* Tell how big L2TP headers are for a particular session. This
 858  * depends on whether sequence numbers are being used.
 859  */
 860 static inline int pppol2tp_l2tp_header_len(struct pppol2tp_session *session)
 861 {
 862         if (session->send_seq)
 863                 return PPPOL2TP_L2TP_HDR_SIZE_SEQ;
 864
 865         return PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
 866 }
 867
 868 /* Build an L2TP header for the session into the buffer provided.
 869  */
 870 static void pppol2tp_build_l2tp_header(struct pppol2tp_session *session,
 871                                        void *buf)
 872 {
 873         __be16 *bufp = buf;
 874         u16 flags = L2TP_HDR_VER;
 875
 876         if (session->send_seq)
 877                 flags |= L2TP_HDRFLAG_S;
 878
 879         /* Setup L2TP header.
 880          * FIXME: Can this ever be unaligned? Is direct dereferencing of
 881          * 16-bit header fields safe here for all architectures?
 882          */
 883         *bufp++ = htons(flags);
 884         *bufp++ = htons(session->tunnel_addr.d_tunnel);
 885         *bufp++ = htons(session->tunnel_addr.d_session);
 886         if (session->send_seq) {
 887                 *bufp++ = htons(session->ns);
 888                 *bufp++ = 0;
 889                 session->ns++;
 890                 PRINTK(session->debug, PPPOL2TP_MSG_SEQ, KERN_DEBUG,
 891                        "%s: updated ns to %hu\n", session->name, session->ns);
 892         }
 893 }
 894
 895 /* This is the sendmsg for the PPPoL2TP pppol2tp_session socket.  We come here
 896  * when a user application does a sendmsg() on the session socket. L2TP and
 897  * PPP headers must be inserted into the user's data.
 898  */
 899 static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *m,
 900                             size_t total_len)
 901 {
 902         static const unsigned char ppph[2] = { 0xff, 0x03 };
 903         struct sock *sk = sock->sk;
 904         struct inet_sock *inet;
 905         __wsum csum;
 906         struct sk_buff *skb;
 907         int error;
 908         int hdr_len;
 909         struct pppol2tp_session *session;
 910         struct pppol2tp_tunnel *tunnel;
 911         struct udphdr *uh;
 912         unsigned int len;
 913         struct sock *sk_tun;
 914         u16 udp_len;
 915
 916         error = -ENOTCONN;
 917         if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
 918                 goto error;
 919
 920         /* Get session and tunnel contexts */
 921         error = -EBADF;
 922         session = pppol2tp_sock_to_session(sk);
 923         if (session == NULL)
 924                 goto error;
 925
 926         sk_tun = session->tunnel_sock;
 927         tunnel = pppol2tp_sock_to_tunnel(sk_tun);
 928         if (tunnel == NULL)
 929                 goto error_put_sess;
 930
 931         /* What header length is configured for this session? */
 932         hdr_len = pppol2tp_l2tp_header_len(session);
 933
 934         /* Allocate a socket buffer */
 935         error = -ENOMEM;
 936         skb = sock_wmalloc(sk, NET_SKB_PAD + sizeof(struct iphdr) +
 937                            sizeof(struct udphdr) + hdr_len +
 938                            sizeof(ppph) + total_len,
 939                            0, GFP_KERNEL);
 940         if (!skb)
 941                 goto error_put_sess_tun;
 942
 943         /* Reserve space for headers. */
 944         skb_reserve(skb, NET_SKB_PAD);
 945         skb_reset_network_header(skb);
 946         skb_reserve(skb, sizeof(struct iphdr));
 947         skb_reset_transport_header(skb);
 948
 949         /* Build UDP header */
 950         inet = inet_sk(sk_tun);
 951         udp_len = hdr_len + sizeof(ppph) + total_len;
 952         uh = (struct udphdr *) skb->data;
 953         uh->source = inet->sport;
 954         uh->dest = inet->dport;
 955         uh->len = htons(udp_len);
 956         uh->check = 0;
 957         skb_put(skb, sizeof(struct udphdr));
 958
 959         /* Build L2TP header */
 960         pppol2tp_build_l2tp_header(session, skb->data);
 961         skb_put(skb, hdr_len);
 962
 963         /* Add PPP header */
 964         skb->data[0] = ppph[0];
 965         skb->data[1] = ppph[1];
 966         skb_put(skb, 2);
 967
 968         /* Copy user data into skb */
 969         error = memcpy_fromiovec(skb->data, m->msg_iov, total_len);
 970         if (error < 0) {
 971                 kfree_skb(skb);
 972                 goto error_put_sess_tun;
 973         }
 974         skb_put(skb, total_len);
 975
 976         /* Calculate UDP checksum if configured to do so */
 977         if (sk_tun->sk_no_check == UDP_CSUM_NOXMIT)
 978                 skb->ip_summed = CHECKSUM_NONE;
 979         else if (!(skb->dst->dev->features & NETIF_F_V4_CSUM)) {
 980                 skb->ip_summed = CHECKSUM_COMPLETE;
 981                 csum = skb_checksum(skb, 0, udp_len, 0);
 982                 uh->check = csum_tcpudp_magic(inet->saddr, inet->daddr,
 983                                               udp_len, IPPROTO_UDP, csum);
 984                 if (uh->check == 0)
 985                         uh->check = CSUM_MANGLED_0;
 986         } else {
 987                 skb->ip_summed = CHECKSUM_PARTIAL;
 988                 skb->csum_start = skb_transport_header(skb) - skb->head;
 989                 skb->csum_offset = offsetof(struct udphdr, check);
 990                 uh->check = ~csum_tcpudp_magic(inet->saddr, inet->daddr,
 991                                                udp_len, IPPROTO_UDP, 0);
 992         }
 993
 994         /* Debug */
 995         if (session->send_seq)
 996                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
 997                        "%s: send %Zd bytes, ns=%hu\n", session->name,
 998                        total_len, session->ns - 1);
 999         else
1000                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
1001                        "%s: send %Zd bytes\n", session->name, total_len);
1002
1003         if (session->debug & PPPOL2TP_MSG_DATA) {
1004                 int i;
1005                 unsigned char *datap = skb->data;
1006
1007                 printk(KERN_DEBUG "%s: xmit:", session->name);
1008                 for (i = 0; i < total_len; i++) {
1009                         printk(" %02X", *datap++);
1010                         if (i == 15) {
1011                                 printk(" ...");
1012                                 break;
1013                         }
1014                 }
1015                 printk("\n");
1016         }
1017
1018         /* Queue the packet to IP for output */
1019         len = skb->len;
1020         error = ip_queue_xmit(skb, 1);
1021
1022         /* Update stats */
1023         if (error >= 0) {
1024                 tunnel->stats.tx_packets++;
1025                 tunnel->stats.tx_bytes += len;
1026                 session->stats.tx_packets++;
1027                 session->stats.tx_bytes += len;
1028         } else {
1029                 tunnel->stats.tx_errors++;
1030                 session->stats.tx_errors++;
1031         }
1032
1033         return error;
1034
1035 error_put_sess_tun:
1036         sock_put(session->tunnel_sock);
1037 error_put_sess:
1038         sock_put(sk);
1039 error:
1040         return error;
1041 }
1042
1043 /* Automatically called when the skb is freed.
1044  */
1045 static void pppol2tp_sock_wfree(struct sk_buff *skb)
1046 {
1047         sock_put(skb->sk);
1048 }
1049
1050 /* For data skbs that we transmit, we associate with the tunnel socket
1051  * but don't do accounting.
1052  */
1053 static inline void pppol2tp_skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
1054 {
1055         sock_hold(sk);
1056         skb->sk = sk;
1057         skb->destructor = pppol2tp_sock_wfree;
1058 }
1059
1060 /* Transmit function called by generic PPP driver.  Sends PPP frame
1061  * over PPPoL2TP socket.
1062  *
1063  * This is almost the same as pppol2tp_sendmsg(), but rather than
1064  * being called with a msghdr from userspace, it is called with a skb
1065  * from the kernel.
1066  *
1067  * The supplied skb from ppp doesn't have enough headroom for the
1068  * insertion of L2TP, UDP and IP headers so we need to allocate more
1069  * headroom in the skb. This will create a cloned skb. But we must be
1070  * careful in the error case because the caller will expect to free
1071  * the skb it supplied, not our cloned skb. So we take care to always
1072  * leave the original skb unfreed if we return an error.
1073  */
1074 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
1075 {
1076         static const u8 ppph[2] = { 0xff, 0x03 };
1077         struct sock *sk = (struct sock *) chan->private;
1078         struct sock *sk_tun;
1079         int hdr_len;
1080         u16 udp_len;
1081         struct pppol2tp_session *session;
1082         struct pppol2tp_tunnel *tunnel;
1083         int rc;
1084         int headroom;
1085         int data_len = skb->len;
1086         struct inet_sock *inet;
1087         __wsum csum;
1088         struct udphdr *uh;
1089         unsigned int len;
1090         int old_headroom;
1091         int new_headroom;
1092
1093         if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED))
1094                 goto abort;
1095
1096         /* Get session and tunnel contexts from the socket */
1097         session = pppol2tp_sock_to_session(sk);
1098         if (session == NULL)
1099                 goto abort;
1100
1101         sk_tun = session->tunnel_sock;
1102         if (sk_tun == NULL)
1103                 goto abort_put_sess;
1104         tunnel = pppol2tp_sock_to_tunnel(sk_tun);
1105         if (tunnel == NULL)
1106                 goto abort_put_sess;
1107
1108         /* What header length is configured for this session? */
1109         hdr_len = pppol2tp_l2tp_header_len(session);
1110
1111         /* Check that there's enough headroom in the skb to insert IP,
1112          * UDP and L2TP and PPP headers. If not enough, expand it to
1113          * make room. Adjust truesize.
1114          */
1115         headroom = NET_SKB_PAD + sizeof(struct iphdr) +
1116                 sizeof(struct udphdr) + hdr_len + sizeof(ppph);
1117         old_headroom = skb_headroom(skb);
1118         if (skb_cow_head(skb, headroom))
1119                 goto abort_put_sess_tun;
1120
1121         new_headroom = skb_headroom(skb);
1122         skb_orphan(skb);
1123         skb->truesize += new_headroom - old_headroom;
1124
1125         /* Setup PPP header */
1126         __skb_push(skb, sizeof(ppph));
1127         skb->data[0] = ppph[0];
1128         skb->data[1] = ppph[1];
1129
1130         /* Setup L2TP header */
1131         pppol2tp_build_l2tp_header(session, __skb_push(skb, hdr_len));
1132
1133         udp_len = sizeof(struct udphdr) + hdr_len + sizeof(ppph) + data_len;
1134
1135         /* Setup UDP header */
1136         inet = inet_sk(sk_tun);
1137         __skb_push(skb, sizeof(*uh));
1138         skb_reset_transport_header(skb);
1139         uh = udp_hdr(skb);
1140         uh->source = inet->sport;
1141         uh->dest = inet->dport;
1142         uh->len = htons(udp_len);
1143         uh->check = 0;
1144
1145         /* Debug */
1146         if (session->send_seq)
1147                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
1148                        "%s: send %d bytes, ns=%hu\n", session->name,
1149                        data_len, session->ns - 1);
1150         else
1151                 PRINTK(session->debug, PPPOL2TP_MSG_DATA, KERN_DEBUG,
1152                        "%s: send %d bytes\n", session->name, data_len);
1153
1154         if (session->debug & PPPOL2TP_MSG_DATA) {
1155                 int i;
1156                 unsigned char *datap = skb->data;
1157
1158                 printk(KERN_DEBUG "%s: xmit:", session->name);
1159                 for (i = 0; i < data_len; i++) {
1160                         printk(" %02X", *datap++);
1161                         if (i == 31) {
1162                                 printk(" ...");
1163                                 break;
1164                         }
1165                 }
1166                 printk("\n");
1167         }
1168
1169         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
1170         IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
1171                               IPSKB_REROUTED);
1172         nf_reset(skb);
1173
1174         /* Get routing info from the tunnel socket */
1175         dst_release(skb->dst);
1176         skb->dst = dst_clone(__sk_dst_get(sk_tun));
1177         pppol2tp_skb_set_owner_w(skb, sk_tun);
1178
1179         /* Calculate UDP checksum if configured to do so */
1180         if (sk_tun->sk_no_check == UDP_CSUM_NOXMIT)
1181                 skb->ip_summed = CHECKSUM_NONE;
1182         else if (!(skb->dst->dev->features & NETIF_F_V4_CSUM)) {
1183                 skb->ip_summed = CHECKSUM_COMPLETE;
1184                 csum = skb_checksum(skb, 0, udp_len, 0);
1185                 uh->check = csum_tcpudp_magic(inet->saddr, inet->daddr,
1186                                               udp_len, IPPROTO_UDP, csum);
1187                 if (uh->check == 0)
1188                         uh->check = CSUM_MANGLED_0;
1189         } else {
1190                 skb->ip_summed = CHECKSUM_PARTIAL;
1191                 skb->csum_start = skb_transport_header(skb) - skb->head;
1192                 skb->csum_offset = offsetof(struct udphdr, check);
1193                 uh->check = ~csum_tcpudp_magic(inet->saddr, inet->daddr,
1194                                                udp_len, IPPROTO_UDP, 0);
1195         }
1196
1197         /* Queue the packet to IP for output */
1198         len = skb->len;
1199         rc = ip_queue_xmit(skb, 1);
1200
1201         /* Update stats */
1202         if (rc >= 0) {
1203                 tunnel->stats.tx_packets++;
1204                 tunnel->stats.tx_bytes += len;
1205                 session->stats.tx_packets++;
1206                 session->stats.tx_bytes += len;
1207         } else {
1208                 tunnel->stats.tx_errors++;
1209                 session->stats.tx_errors++;
1210         }
1211
1212         sock_put(sk_tun);
1213         sock_put(sk);
1214         return 1;
1215
1216 abort_put_sess_tun:
1217         sock_put(sk_tun);
1218 abort_put_sess:
1219         sock_put(sk);
1220 abort:
1221         /* Free the original skb */
1222         kfree_skb(skb);
1223         return 1;
1224 }
1225
1226 /*****************************************************************************
1227  * Session (and tunnel control) socket create/destroy.
1228  *****************************************************************************/
1229
1230 /* When the tunnel UDP socket is closed, all the attached sockets need to go
1231  * too.
1232  */
1233 static void pppol2tp_tunnel_closeall(struct pppol2tp_tunnel *tunnel)
1234 {
1235         int hash;
1236         struct hlist_node *walk;
1237         struct hlist_node *tmp;
1238         struct pppol2tp_session *session;
1239         struct sock *sk;
1240
1241         BUG_ON(tunnel == NULL);
1242
1243         PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1244                "%s: closing all sessions...\n", tunnel->name);
1245
1246         write_lock_bh(&tunnel->hlist_lock);
1247         for (hash = 0; hash < PPPOL2TP_HASH_SIZE; hash++) {
1248 again:
1249                 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
1250                         struct sk_buff *skb;
1251
1252                         session = hlist_entry(walk, struct pppol2tp_session, hlist);
1253
1254                         sk = session->sock;
1255
1256                         PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1257                                "%s: closing session\n", session->name);
1258
1259                         hlist_del_init(&session->hlist);
1260
1261                         /* Since we should hold the sock lock while
1262                          * doing any unbinding, we need to release the
1263                          * lock we're holding before taking that lock.
1264                          * Hold a reference to the sock so it doesn't
1265                          * disappear as we're jumping between locks.
1266                          */
1267                         sock_hold(sk);
1268                         write_unlock_bh(&tunnel->hlist_lock);
1269                         lock_sock(sk);
1270
1271                         if (sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND)) {
1272                                 pppox_unbind_sock(sk);
1273                                 sk->sk_state = PPPOX_DEAD;
1274                                 sk->sk_state_change(sk);
1275                         }
1276
1277                         /* Purge any queued data */
1278                         skb_queue_purge(&sk->sk_receive_queue);
1279                         skb_queue_purge(&sk->sk_write_queue);
1280                         while ((skb = skb_dequeue(&session->reorder_q))) {
1281                                 kfree_skb(skb);
1282                                 sock_put(sk);
1283                         }
1284
1285                         release_sock(sk);
1286                         sock_put(sk);
1287
1288                         /* Now restart from the beginning of this hash
1289                          * chain.  We always remove a session from the
1290                          * list so we are guaranteed to make forward
1291                          * progress.
1292                          */
1293                         write_lock_bh(&tunnel->hlist_lock);
1294                         goto again;
1295                 }
1296         }
1297         write_unlock_bh(&tunnel->hlist_lock);
1298 }
1299
1300 /* Really kill the tunnel.
1301  * Come here only when all sessions have been cleared from the tunnel.
1302  */
1303 static void pppol2tp_tunnel_free(struct pppol2tp_tunnel *tunnel)
1304 {
1305         struct pppol2tp_net *pn = pppol2tp_pernet(tunnel->pppol2tp_net);
1306
1307         /* Remove from socket list */
1308         write_lock_bh(&pn->pppol2tp_tunnel_list_lock);
1309         list_del_init(&tunnel->list);
1310         write_unlock_bh(&pn->pppol2tp_tunnel_list_lock);
1311
1312         atomic_dec(&pppol2tp_tunnel_count);
1313         kfree(tunnel);
1314 }
1315
1316 /* Tunnel UDP socket destruct hook.
1317  * The tunnel context is deleted only when all session sockets have been
1318  * closed.
1319  */
1320 static void pppol2tp_tunnel_destruct(struct sock *sk)
1321 {
1322         struct pppol2tp_tunnel *tunnel;
1323
1324         tunnel = sk->sk_user_data;
1325         if (tunnel == NULL)
1326                 goto end;
1327
1328         PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1329                "%s: closing...\n", tunnel->name);
1330
1331         /* Close all sessions */
1332         pppol2tp_tunnel_closeall(tunnel);
1333
1334         /* No longer an encapsulation socket. See net/ipv4/udp.c */
1335         (udp_sk(sk))->encap_type = 0;
1336         (udp_sk(sk))->encap_rcv = NULL;
1337
1338         /* Remove hooks into tunnel socket */
1339         tunnel->sock = NULL;
1340         sk->sk_destruct = tunnel->old_sk_destruct;
1341         sk->sk_user_data = NULL;
1342
1343         /* Call original (UDP) socket descructor */
1344         if (sk->sk_destruct != NULL)
1345                 (*sk->sk_destruct)(sk);
1346
1347         pppol2tp_tunnel_dec_refcount(tunnel);
1348
1349 end:
1350         return;
1351 }
1352
1353 /* Really kill the session socket. (Called from sock_put() if
1354  * refcnt == 0.)
1355  */
1356 static void pppol2tp_session_destruct(struct sock *sk)
1357 {
1358         struct pppol2tp_session *session = NULL;
1359
1360         if (sk->sk_user_data != NULL) {
1361                 struct pppol2tp_tunnel *tunnel;
1362
1363                 session = sk->sk_user_data;
1364                 if (session == NULL)
1365                         goto out;
1366
1367                 BUG_ON(session->magic != L2TP_SESSION_MAGIC);
1368
1369                 /* Don't use pppol2tp_sock_to_tunnel() here to
1370                  * get the tunnel context because the tunnel
1371                  * socket might have already been closed (its
1372                  * sk->sk_user_data will be NULL) so use the
1373                  * session's private tunnel ptr instead.
1374                  */
1375                 tunnel = session->tunnel;
1376                 if (tunnel != NULL) {
1377                         BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
1378
1379                         /* If session_id is zero, this is a null
1380                          * session context, which was created for a
1381                          * socket that is being used only to manage
1382                          * tunnels.
1383                          */
1384                         if (session->tunnel_addr.s_session != 0) {
1385                                 /* Delete the session socket from the
1386                                  * hash
1387                                  */
1388                                 write_lock_bh(&tunnel->hlist_lock);
1389                                 hlist_del_init(&session->hlist);
1390                                 write_unlock_bh(&tunnel->hlist_lock);
1391
1392                                 atomic_dec(&pppol2tp_session_count);
1393                         }
1394
1395                         /* This will delete the tunnel context if this
1396                          * is the last session on the tunnel.
1397                          */
1398                         session->tunnel = NULL;
1399                         session->tunnel_sock = NULL;
1400                         pppol2tp_tunnel_dec_refcount(tunnel);
1401                 }
1402         }
1403
1404         kfree(session);
1405 out:
1406         return;
1407 }
1408
1409 /* Called when the PPPoX socket (session) is closed.
1410  */
1411 static int pppol2tp_release(struct socket *sock)
1412 {
1413         struct sock *sk = sock->sk;
1414         struct pppol2tp_session *session;
1415         int error;
1416
1417         if (!sk)
1418                 return 0;
1419
1420         error = -EBADF;
1421         lock_sock(sk);
1422         if (sock_flag(sk, SOCK_DEAD) != 0)
1423                 goto error;
1424
1425         pppox_unbind_sock(sk);
1426
1427         /* Signal the death of the socket. */
1428         sk->sk_state = PPPOX_DEAD;
1429         sock_orphan(sk);
1430         sock->sk = NULL;
1431
1432         session = pppol2tp_sock_to_session(sk);
1433
1434         /* Purge any queued data */
1435         skb_queue_purge(&sk->sk_receive_queue);
1436         skb_queue_purge(&sk->sk_write_queue);
1437         if (session != NULL) {
1438                 struct sk_buff *skb;
1439                 while ((skb = skb_dequeue(&session->reorder_q))) {
1440                         kfree_skb(skb);
1441                         sock_put(sk);
1442                 }
1443                 sock_put(sk);
1444         }
1445
1446         release_sock(sk);
1447
1448         /* This will delete the session context via
1449          * pppol2tp_session_destruct() if the socket's refcnt drops to
1450          * zero.
1451          */
1452         sock_put(sk);
1453
1454         return 0;
1455
1456 error:
1457         release_sock(sk);
1458         return error;
1459 }
1460
1461 /* Internal function to prepare a tunnel (UDP) socket to have PPPoX
1462  * sockets attached to it.
1463  */
1464 static struct sock *pppol2tp_prepare_tunnel_socket(struct net *net,
1465                                         int fd, u16 tunnel_id, int *error)
1466 {
1467         int err;
1468         struct socket *sock = NULL;
1469         struct sock *sk;
1470         struct pppol2tp_tunnel *tunnel;
1471         struct pppol2tp_net *pn;
1472         struct sock *ret = NULL;
1473
1474         /* Get the tunnel UDP socket from the fd, which was opened by
1475          * the userspace L2TP daemon.
1476          */
1477         err = -EBADF;
1478         sock = sockfd_lookup(fd, &err);
1479         if (!sock) {
1480                 PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_ERR,
1481                        "tunl %hu: sockfd_lookup(fd=%d) returned %d\n",
1482                        tunnel_id, fd, err);
1483                 goto err;
1484         }
1485
1486         sk = sock->sk;
1487
1488         /* Quick sanity checks */
1489         err = -EPROTONOSUPPORT;
1490         if (sk->sk_protocol != IPPROTO_UDP) {
1491                 PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_ERR,
1492                        "tunl %hu: fd %d wrong protocol, got %d, expected %d\n",
1493                        tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP);
1494                 goto err;
1495         }
1496         err = -EAFNOSUPPORT;
1497         if (sock->ops->family != AF_INET) {
1498                 PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_ERR,
1499                        "tunl %hu: fd %d wrong family, got %d, expected %d\n",
1500                        tunnel_id, fd, sock->ops->family, AF_INET);
1501                 goto err;
1502         }
1503
1504         err = -ENOTCONN;
1505
1506         /* Check if this socket has already been prepped */
1507         tunnel = (struct pppol2tp_tunnel *)sk->sk_user_data;
1508         if (tunnel != NULL) {
1509                 /* User-data field already set */
1510                 err = -EBUSY;
1511                 BUG_ON(tunnel->magic != L2TP_TUNNEL_MAGIC);
1512
1513                 /* This socket has already been prepped */
1514                 ret = tunnel->sock;
1515                 goto out;
1516         }
1517
1518         /* This socket is available and needs prepping. Create a new tunnel
1519          * context and init it.
1520          */
1521         sk->sk_user_data = tunnel = kzalloc(sizeof(struct pppol2tp_tunnel), GFP_KERNEL);
1522         if (sk->sk_user_data == NULL) {
1523                 err = -ENOMEM;
1524                 goto err;
1525         }
1526
1527         tunnel->magic = L2TP_TUNNEL_MAGIC;
1528         sprintf(&tunnel->name[0], "tunl %hu", tunnel_id);
1529
1530         tunnel->stats.tunnel_id = tunnel_id;
1531         tunnel->debug = PPPOL2TP_DEFAULT_DEBUG_FLAGS;
1532
1533         /* Hook on the tunnel socket destructor so that we can cleanup
1534          * if the tunnel socket goes away.
1535          */
1536         tunnel->old_sk_destruct = sk->sk_destruct;
1537         sk->sk_destruct = &pppol2tp_tunnel_destruct;
1538
1539         tunnel->sock = sk;
1540         sk->sk_allocation = GFP_ATOMIC;
1541
1542         /* Misc init */
1543         rwlock_init(&tunnel->hlist_lock);
1544
1545         /* The net we belong to */
1546         tunnel->pppol2tp_net = net;
1547         pn = pppol2tp_pernet(net);
1548
1549         /* Add tunnel to our list */
1550         INIT_LIST_HEAD(&tunnel->list);
1551         write_lock_bh(&pn->pppol2tp_tunnel_list_lock);
1552         list_add(&tunnel->list, &pn->pppol2tp_tunnel_list);
1553         write_unlock_bh(&pn->pppol2tp_tunnel_list_lock);
1554         atomic_inc(&pppol2tp_tunnel_count);
1555
1556         /* Bump the reference count. The tunnel context is deleted
1557          * only when this drops to zero.
1558          */
1559         pppol2tp_tunnel_inc_refcount(tunnel);
1560
1561         /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */
1562         (udp_sk(sk))->encap_type = UDP_ENCAP_L2TPINUDP;
1563         (udp_sk(sk))->encap_rcv = pppol2tp_udp_encap_recv;
1564
1565         ret = tunnel->sock;
1566
1567         *error = 0;
1568 out:
1569         if (sock)
1570                 sockfd_put(sock);
1571
1572         return ret;
1573
1574 err:
1575         *error = err;
1576         goto out;
1577 }
1578
1579 static struct proto pppol2tp_sk_proto = {
1580         .name     = "PPPOL2TP",
1581         .owner    = THIS_MODULE,
1582         .obj_size = sizeof(struct pppox_sock),
1583 };
1584
1585 /* socket() handler. Initialize a new struct sock.
1586  */
1587 static int pppol2tp_create(struct net *net, struct socket *sock)
1588 {
1589         int error = -ENOMEM;
1590         struct sock *sk;
1591
1592         sk = sk_alloc(net, PF_PPPOX, GFP_KERNEL, &pppol2tp_sk_proto);
1593         if (!sk)
1594                 goto out;
1595
1596         sock_init_data(sock, sk);
1597
1598         sock->state  = SS_UNCONNECTED;
1599         sock->ops    = &pppol2tp_ops;
1600
1601         sk->sk_backlog_rcv = pppol2tp_recv_core;
1602         sk->sk_protocol    = PX_PROTO_OL2TP;
1603         sk->sk_family      = PF_PPPOX;
1604         sk->sk_state       = PPPOX_NONE;
1605         sk->sk_type        = SOCK_STREAM;
1606         sk->sk_destruct    = pppol2tp_session_destruct;
1607
1608         error = 0;
1609
1610 out:
1611         return error;
1612 }
1613
1614 /* connect() handler. Attach a PPPoX socket to a tunnel UDP socket
1615  */
1616 static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr,
1617                             int sockaddr_len, int flags)
1618 {
1619         struct sock *sk = sock->sk;
1620         struct sockaddr_pppol2tp *sp = (struct sockaddr_pppol2tp *) uservaddr;
1621         struct pppox_sock *po = pppox_sk(sk);
1622         struct sock *tunnel_sock = NULL;
1623         struct pppol2tp_session *session = NULL;
1624         struct pppol2tp_tunnel *tunnel;
1625         struct dst_entry *dst;
1626         int error = 0;
1627
1628         lock_sock(sk);
1629
1630         error = -EINVAL;
1631         if (sp->sa_protocol != PX_PROTO_OL2TP)
1632                 goto end;
1633
1634         /* Check for already bound sockets */
1635         error = -EBUSY;
1636         if (sk->sk_state & PPPOX_CONNECTED)
1637                 goto end;
1638
1639         /* We don't supporting rebinding anyway */
1640         error = -EALREADY;
1641         if (sk->sk_user_data)
1642                 goto end; /* socket is already attached */
1643
1644         /* Don't bind if s_tunnel is 0 */
1645         error = -EINVAL;
1646         if (sp->pppol2tp.s_tunnel == 0)
1647                 goto end;
1648
1649         /* Special case: prepare tunnel socket if s_session and
1650          * d_session is 0. Otherwise look up tunnel using supplied
1651          * tunnel id.
1652          */
1653         if ((sp->pppol2tp.s_session == 0) && (sp->pppol2tp.d_session == 0)) {
1654                 tunnel_sock = pppol2tp_prepare_tunnel_socket(sock_net(sk),
1655                                                              sp->pppol2tp.fd,
1656                                                              sp->pppol2tp.s_tunnel,
1657                                                              &error);
1658                 if (tunnel_sock == NULL)
1659                         goto end;
1660
1661                 tunnel = tunnel_sock->sk_user_data;
1662         } else {
1663                 tunnel = pppol2tp_tunnel_find(sock_net(sk), sp->pppol2tp.s_tunnel);
1664
1665                 /* Error if we can't find the tunnel */
1666                 error = -ENOENT;
1667                 if (tunnel == NULL)
1668                         goto end;
1669
1670                 tunnel_sock = tunnel->sock;
1671         }
1672
1673         /* Check that this session doesn't already exist */
1674         error = -EEXIST;
1675         session = pppol2tp_session_find(tunnel, sp->pppol2tp.s_session);
1676         if (session != NULL)
1677                 goto end;
1678
1679         /* Allocate and initialize a new session context. */
1680         session = kzalloc(sizeof(struct pppol2tp_session), GFP_KERNEL);
1681         if (session == NULL) {
1682                 error = -ENOMEM;
1683                 goto end;
1684         }
1685
1686         skb_queue_head_init(&session->reorder_q);
1687
1688         session->magic       = L2TP_SESSION_MAGIC;
1689         session->owner       = current->pid;
1690         session->sock        = sk;
1691         session->tunnel      = tunnel;
1692         session->tunnel_sock = tunnel_sock;
1693         session->tunnel_addr = sp->pppol2tp;
1694         sprintf(&session->name[0], "sess %hu/%hu",
1695                 session->tunnel_addr.s_tunnel,
1696                 session->tunnel_addr.s_session);
1697
1698         session->stats.tunnel_id  = session->tunnel_addr.s_tunnel;
1699         session->stats.session_id = session->tunnel_addr.s_session;
1700
1701         INIT_HLIST_NODE(&session->hlist);
1702
1703         /* Inherit debug options from tunnel */
1704         session->debug = tunnel->debug;
1705
1706         /* Default MTU must allow space for UDP/L2TP/PPP
1707          * headers.
1708          */
1709         session->mtu = session->mru = 1500 - PPPOL2TP_HEADER_OVERHEAD;
1710
1711         /* If PMTU discovery was enabled, use the MTU that was discovered */
1712         dst = sk_dst_get(sk);
1713         if (dst != NULL) {
1714                 u32 pmtu = dst_mtu(__sk_dst_get(sk));
1715                 if (pmtu != 0)
1716                         session->mtu = session->mru = pmtu -
1717                                 PPPOL2TP_HEADER_OVERHEAD;
1718                 dst_release(dst);
1719         }
1720
1721         /* Special case: if source & dest session_id == 0x0000, this socket is
1722          * being created to manage the tunnel. Don't add the session to the
1723          * session hash list, just set up the internal context for use by
1724          * ioctl() and sockopt() handlers.
1725          */
1726         if ((session->tunnel_addr.s_session == 0) &&
1727             (session->tunnel_addr.d_session == 0)) {
1728                 error = 0;
1729                 sk->sk_user_data = session;
1730                 goto out_no_ppp;
1731         }
1732
1733         /* Get tunnel context from the tunnel socket */
1734         tunnel = pppol2tp_sock_to_tunnel(tunnel_sock);
1735         if (tunnel == NULL) {
1736                 error = -EBADF;
1737                 goto end;
1738         }
1739
1740         /* Right now, because we don't have a way to push the incoming skb's
1741          * straight through the UDP layer, the only header we need to worry
1742          * about is the L2TP header. This size is different depending on
1743          * whether sequence numbers are enabled for the data channel.
1744          */
1745         po->chan.hdrlen = PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
1746
1747         po->chan.private = sk;
1748         po->chan.ops     = &pppol2tp_chan_ops;
1749         po->chan.mtu     = session->mtu;
1750
1751         error = ppp_register_net_channel(sock_net(sk), &po->chan);
1752         if (error)
1753                 goto end_put_tun;
1754
1755         /* This is how we get the session context from the socket. */
1756         sk->sk_user_data = session;
1757
1758         /* Add session to the tunnel's hash list */
1759         write_lock_bh(&tunnel->hlist_lock);
1760         hlist_add_head(&session->hlist,
1761                        pppol2tp_session_id_hash(tunnel,
1762                                                 session->tunnel_addr.s_session));
1763         write_unlock_bh(&tunnel->hlist_lock);
1764
1765         atomic_inc(&pppol2tp_session_count);
1766
1767 out_no_ppp:
1768         pppol2tp_tunnel_inc_refcount(tunnel);
1769         sk->sk_state = PPPOX_CONNECTED;
1770         PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1771                "%s: created\n", session->name);
1772
1773 end_put_tun:
1774         sock_put(tunnel_sock);
1775 end:
1776         release_sock(sk);
1777
1778         if (error != 0) {
1779                 if (session)
1780                         PRINTK(session->debug,
1781                                 PPPOL2TP_MSG_CONTROL, KERN_WARNING,
1782                                 "%s: connect failed: %d\n",
1783                                 session->name, error);
1784                 else
1785                         PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_WARNING,
1786                                 "connect failed: %d\n", error);
1787         }
1788
1789         return error;
1790 }
1791
1792 /* getname() support.
1793  */
1794 static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr,
1795                             int *usockaddr_len, int peer)
1796 {
1797         int len = sizeof(struct sockaddr_pppol2tp);
1798         struct sockaddr_pppol2tp sp;
1799         int error = 0;
1800         struct pppol2tp_session *session;
1801
1802         error = -ENOTCONN;
1803         if (sock->sk->sk_state != PPPOX_CONNECTED)
1804                 goto end;
1805
1806         session = pppol2tp_sock_to_session(sock->sk);
1807         if (session == NULL) {
1808                 error = -EBADF;
1809                 goto end;
1810         }
1811
1812         sp.sa_family    = AF_PPPOX;
1813         sp.sa_protocol  = PX_PROTO_OL2TP;
1814         memcpy(&sp.pppol2tp, &session->tunnel_addr,
1815                sizeof(struct pppol2tp_addr));
1816
1817         memcpy(uaddr, &sp, len);
1818
1819         *usockaddr_len = len;
1820
1821         error = 0;
1822         sock_put(sock->sk);
1823
1824 end:
1825         return error;
1826 }
1827
1828 /****************************************************************************
1829  * ioctl() handlers.
1830  *
1831  * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
1832  * sockets. However, in order to control kernel tunnel features, we allow
1833  * userspace to create a special "tunnel" PPPoX socket which is used for
1834  * control only.  Tunnel PPPoX sockets have session_id == 0 and simply allow
1835  * the user application to issue L2TP setsockopt(), getsockopt() and ioctl()
1836  * calls.
1837  ****************************************************************************/
1838
1839 /* Session ioctl helper.
1840  */
1841 static int pppol2tp_session_ioctl(struct pppol2tp_session *session,
1842                                   unsigned int cmd, unsigned long arg)
1843 {
1844         struct ifreq ifr;
1845         int err = 0;
1846         struct sock *sk = session->sock;
1847         int val = (int) arg;
1848
1849         PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_DEBUG,
1850                "%s: pppol2tp_session_ioctl(cmd=%#x, arg=%#lx)\n",
1851                session->name, cmd, arg);
1852
1853         sock_hold(sk);
1854
1855         switch (cmd) {
1856         case SIOCGIFMTU:
1857                 err = -ENXIO;
1858                 if (!(sk->sk_state & PPPOX_CONNECTED))
1859                         break;
1860
1861                 err = -EFAULT;
1862                 if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq)))
1863                         break;
1864                 ifr.ifr_mtu = session->mtu;
1865                 if (copy_to_user((void __user *) arg, &ifr, sizeof(struct ifreq)))
1866                         break;
1867
1868                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1869                        "%s: get mtu=%d\n", session->name, session->mtu);
1870                 err = 0;
1871                 break;
1872
1873         case SIOCSIFMTU:
1874                 err = -ENXIO;
1875                 if (!(sk->sk_state & PPPOX_CONNECTED))
1876                         break;
1877
1878                 err = -EFAULT;
1879                 if (copy_from_user(&ifr, (void __user *) arg, sizeof(struct ifreq)))
1880                         break;
1881
1882                 session->mtu = ifr.ifr_mtu;
1883
1884                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1885                        "%s: set mtu=%d\n", session->name, session->mtu);
1886                 err = 0;
1887                 break;
1888
1889         case PPPIOCGMRU:
1890                 err = -ENXIO;
1891                 if (!(sk->sk_state & PPPOX_CONNECTED))
1892                         break;
1893
1894                 err = -EFAULT;
1895                 if (put_user(session->mru, (int __user *) arg))
1896                         break;
1897
1898                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1899                        "%s: get mru=%d\n", session->name, session->mru);
1900                 err = 0;
1901                 break;
1902
1903         case PPPIOCSMRU:
1904                 err = -ENXIO;
1905                 if (!(sk->sk_state & PPPOX_CONNECTED))
1906                         break;
1907
1908                 err = -EFAULT;
1909                 if (get_user(val,(int __user *) arg))
1910                         break;
1911
1912                 session->mru = val;
1913                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1914                        "%s: set mru=%d\n", session->name, session->mru);
1915                 err = 0;
1916                 break;
1917
1918         case PPPIOCGFLAGS:
1919                 err = -EFAULT;
1920                 if (put_user(session->flags, (int __user *) arg))
1921                         break;
1922
1923                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1924                        "%s: get flags=%d\n", session->name, session->flags);
1925                 err = 0;
1926                 break;
1927
1928         case PPPIOCSFLAGS:
1929                 err = -EFAULT;
1930                 if (get_user(val, (int __user *) arg))
1931                         break;
1932                 session->flags = val;
1933                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1934                        "%s: set flags=%d\n", session->name, session->flags);
1935                 err = 0;
1936                 break;
1937
1938         case PPPIOCGL2TPSTATS:
1939                 err = -ENXIO;
1940                 if (!(sk->sk_state & PPPOX_CONNECTED))
1941                         break;
1942
1943                 if (copy_to_user((void __user *) arg, &session->stats,
1944                                  sizeof(session->stats)))
1945                         break;
1946                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
1947                        "%s: get L2TP stats\n", session->name);
1948                 err = 0;
1949                 break;
1950
1951         default:
1952                 err = -ENOSYS;
1953                 break;
1954         }
1955
1956         sock_put(sk);
1957
1958         return err;
1959 }
1960
1961 /* Tunnel ioctl helper.
1962  *
1963  * Note the special handling for PPPIOCGL2TPSTATS below. If the ioctl data
1964  * specifies a session_id, the session ioctl handler is called. This allows an
1965  * application to retrieve session stats via a tunnel socket.
1966  */
1967 static int pppol2tp_tunnel_ioctl(struct pppol2tp_tunnel *tunnel,
1968                                  unsigned int cmd, unsigned long arg)
1969 {
1970         int err = 0;
1971         struct sock *sk = tunnel->sock;
1972         struct pppol2tp_ioc_stats stats_req;
1973
1974         PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_DEBUG,
1975                "%s: pppol2tp_tunnel_ioctl(cmd=%#x, arg=%#lx)\n", tunnel->name,
1976                cmd, arg);
1977
1978         sock_hold(sk);
1979
1980         switch (cmd) {
1981         case PPPIOCGL2TPSTATS:
1982                 err = -ENXIO;
1983                 if (!(sk->sk_state & PPPOX_CONNECTED))
1984                         break;
1985
1986                 if (copy_from_user(&stats_req, (void __user *) arg,
1987                                    sizeof(stats_req))) {
1988                         err = -EFAULT;
1989                         break;
1990                 }
1991                 if (stats_req.session_id != 0) {
1992                         /* resend to session ioctl handler */
1993                         struct pppol2tp_session *session =
1994                                 pppol2tp_session_find(tunnel, stats_req.session_id);
1995                         if (session != NULL)
1996                                 err = pppol2tp_session_ioctl(session, cmd, arg);
1997                         else
1998                                 err = -EBADR;
1999                         break;
2000                 }
2001 #ifdef CONFIG_XFRM
2002                 tunnel->stats.using_ipsec = (sk->sk_policy[0] || sk->sk_policy[1]) ? 1 : 0;
2003 #endif
2004                 if (copy_to_user((void __user *) arg, &tunnel->stats,
2005                                  sizeof(tunnel->stats))) {
2006                         err = -EFAULT;
2007                         break;
2008                 }
2009                 PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2010                        "%s: get L2TP stats\n", tunnel->name);
2011                 err = 0;
2012                 break;
2013
2014         default:
2015                 err = -ENOSYS;
2016                 break;
2017         }
2018
2019         sock_put(sk);
2020
2021         return err;
2022 }
2023
2024 /* Main ioctl() handler.
2025  * Dispatch to tunnel or session helpers depending on the socket.
2026  */
2027 static int pppol2tp_ioctl(struct socket *sock, unsigned int cmd,
2028                           unsigned long arg)
2029 {
2030         struct sock *sk = sock->sk;
2031         struct pppol2tp_session *session;
2032         struct pppol2tp_tunnel *tunnel;
2033         int err;
2034
2035         if (!sk)
2036                 return 0;
2037
2038         err = -EBADF;
2039         if (sock_flag(sk, SOCK_DEAD) != 0)
2040                 goto end;
2041
2042         err = -ENOTCONN;
2043         if ((sk->sk_user_data == NULL) ||
2044             (!(sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND))))
2045                 goto end;
2046
2047         /* Get session context from the socket */
2048         err = -EBADF;
2049         session = pppol2tp_sock_to_session(sk);
2050         if (session == NULL)
2051                 goto end;
2052
2053         /* Special case: if session's session_id is zero, treat ioctl as a
2054          * tunnel ioctl
2055          */
2056         if ((session->tunnel_addr.s_session == 0) &&
2057             (session->tunnel_addr.d_session == 0)) {
2058                 err = -EBADF;
2059                 tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
2060                 if (tunnel == NULL)
2061                         goto end_put_sess;
2062
2063                 err = pppol2tp_tunnel_ioctl(tunnel, cmd, arg);
2064                 sock_put(session->tunnel_sock);
2065                 goto end_put_sess;
2066         }
2067
2068         err = pppol2tp_session_ioctl(session, cmd, arg);
2069
2070 end_put_sess:
2071         sock_put(sk);
2072 end:
2073         return err;
2074 }
2075
2076 /*****************************************************************************
2077  * setsockopt() / getsockopt() support.
2078  *
2079  * The PPPoX socket is created for L2TP sessions: tunnels have their own UDP
2080  * sockets. In order to control kernel tunnel features, we allow userspace to
2081  * create a special "tunnel" PPPoX socket which is used for control only.
2082  * Tunnel PPPoX sockets have session_id == 0 and simply allow the user
2083  * application to issue L2TP setsockopt(), getsockopt() and ioctl() calls.
2084  *****************************************************************************/
2085
2086 /* Tunnel setsockopt() helper.
2087  */
2088 static int pppol2tp_tunnel_setsockopt(struct sock *sk,
2089                                       struct pppol2tp_tunnel *tunnel,
2090                                       int optname, int val)
2091 {
2092         int err = 0;
2093
2094         switch (optname) {
2095         case PPPOL2TP_SO_DEBUG:
2096                 tunnel->debug = val;
2097                 PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2098                        "%s: set debug=%x\n", tunnel->name, tunnel->debug);
2099                 break;
2100
2101         default:
2102                 err = -ENOPROTOOPT;
2103                 break;
2104         }
2105
2106         return err;
2107 }
2108
2109 /* Session setsockopt helper.
2110  */
2111 static int pppol2tp_session_setsockopt(struct sock *sk,
2112                                        struct pppol2tp_session *session,
2113                                        int optname, int val)
2114 {
2115         int err = 0;
2116
2117         switch (optname) {
2118         case PPPOL2TP_SO_RECVSEQ:
2119                 if ((val != 0) && (val != 1)) {
2120                         err = -EINVAL;
2121                         break;
2122                 }
2123                 session->recv_seq = val ? -1 : 0;
2124                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2125                        "%s: set recv_seq=%d\n", session->name,
2126                        session->recv_seq);
2127                 break;
2128
2129         case PPPOL2TP_SO_SENDSEQ:
2130                 if ((val != 0) && (val != 1)) {
2131                         err = -EINVAL;
2132                         break;
2133                 }
2134                 session->send_seq = val ? -1 : 0;
2135                 {
2136                         struct sock *ssk      = session->sock;
2137                         struct pppox_sock *po = pppox_sk(ssk);
2138                         po->chan.hdrlen = val ? PPPOL2TP_L2TP_HDR_SIZE_SEQ :
2139                                 PPPOL2TP_L2TP_HDR_SIZE_NOSEQ;
2140                 }
2141                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2142                        "%s: set send_seq=%d\n", session->name, session->send_seq);
2143                 break;
2144
2145         case PPPOL2TP_SO_LNSMODE:
2146                 if ((val != 0) && (val != 1)) {
2147                         err = -EINVAL;
2148                         break;
2149                 }
2150                 session->lns_mode = val ? -1 : 0;
2151                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2152                        "%s: set lns_mode=%d\n", session->name,
2153                        session->lns_mode);
2154                 break;
2155
2156         case PPPOL2TP_SO_DEBUG:
2157                 session->debug = val;
2158                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2159                        "%s: set debug=%x\n", session->name, session->debug);
2160                 break;
2161
2162         case PPPOL2TP_SO_REORDERTO:
2163                 session->reorder_timeout = msecs_to_jiffies(val);
2164                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2165                        "%s: set reorder_timeout=%d\n", session->name,
2166                        session->reorder_timeout);
2167                 break;
2168
2169         default:
2170                 err = -ENOPROTOOPT;
2171                 break;
2172         }
2173
2174         return err;
2175 }
2176
2177 /* Main setsockopt() entry point.
2178  * Does API checks, then calls either the tunnel or session setsockopt
2179  * handler, according to whether the PPPoL2TP socket is a for a regular
2180  * session or the special tunnel type.
2181  */
2182 static int pppol2tp_setsockopt(struct socket *sock, int level, int optname,
2183                                char __user *optval, int optlen)
2184 {
2185         struct sock *sk = sock->sk;
2186         struct pppol2tp_session *session = sk->sk_user_data;
2187         struct pppol2tp_tunnel *tunnel;
2188         int val;
2189         int err;
2190
2191         if (level != SOL_PPPOL2TP)
2192                 return udp_prot.setsockopt(sk, level, optname, optval, optlen);
2193
2194         if (optlen < sizeof(int))
2195                 return -EINVAL;
2196
2197         if (get_user(val, (int __user *)optval))
2198                 return -EFAULT;
2199
2200         err = -ENOTCONN;
2201         if (sk->sk_user_data == NULL)
2202                 goto end;
2203
2204         /* Get session context from the socket */
2205         err = -EBADF;
2206         session = pppol2tp_sock_to_session(sk);
2207         if (session == NULL)
2208                 goto end;
2209
2210         /* Special case: if session_id == 0x0000, treat as operation on tunnel
2211          */
2212         if ((session->tunnel_addr.s_session == 0) &&
2213             (session->tunnel_addr.d_session == 0)) {
2214                 err = -EBADF;
2215                 tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
2216                 if (tunnel == NULL)
2217                         goto end_put_sess;
2218
2219                 err = pppol2tp_tunnel_setsockopt(sk, tunnel, optname, val);
2220                 sock_put(session->tunnel_sock);
2221         } else
2222                 err = pppol2tp_session_setsockopt(sk, session, optname, val);
2223
2224         err = 0;
2225
2226 end_put_sess:
2227         sock_put(sk);
2228 end:
2229         return err;
2230 }
2231
2232 /* Tunnel getsockopt helper. Called with sock locked.
2233  */
2234 static int pppol2tp_tunnel_getsockopt(struct sock *sk,
2235                                       struct pppol2tp_tunnel *tunnel,
2236                                       int optname, int *val)
2237 {
2238         int err = 0;
2239
2240         switch (optname) {
2241         case PPPOL2TP_SO_DEBUG:
2242                 *val = tunnel->debug;
2243                 PRINTK(tunnel->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2244                        "%s: get debug=%x\n", tunnel->name, tunnel->debug);
2245                 break;
2246
2247         default:
2248                 err = -ENOPROTOOPT;
2249                 break;
2250         }
2251
2252         return err;
2253 }
2254
2255 /* Session getsockopt helper. Called with sock locked.
2256  */
2257 static int pppol2tp_session_getsockopt(struct sock *sk,
2258                                        struct pppol2tp_session *session,
2259                                        int optname, int *val)
2260 {
2261         int err = 0;
2262
2263         switch (optname) {
2264         case PPPOL2TP_SO_RECVSEQ:
2265                 *val = session->recv_seq;
2266                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2267                        "%s: get recv_seq=%d\n", session->name, *val);
2268                 break;
2269
2270         case PPPOL2TP_SO_SENDSEQ:
2271                 *val = session->send_seq;
2272                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2273                        "%s: get send_seq=%d\n", session->name, *val);
2274                 break;
2275
2276         case PPPOL2TP_SO_LNSMODE:
2277                 *val = session->lns_mode;
2278                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2279                        "%s: get lns_mode=%d\n", session->name, *val);
2280                 break;
2281
2282         case PPPOL2TP_SO_DEBUG:
2283                 *val = session->debug;
2284                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2285                        "%s: get debug=%d\n", session->name, *val);
2286                 break;
2287
2288         case PPPOL2TP_SO_REORDERTO:
2289                 *val = (int) jiffies_to_msecs(session->reorder_timeout);
2290                 PRINTK(session->debug, PPPOL2TP_MSG_CONTROL, KERN_INFO,
2291                        "%s: get reorder_timeout=%d\n", session->name, *val);
2292                 break;
2293
2294         default:
2295                 err = -ENOPROTOOPT;
2296         }
2297
2298         return err;
2299 }
2300
2301 /* Main getsockopt() entry point.
2302  * Does API checks, then calls either the tunnel or session getsockopt
2303  * handler, according to whether the PPPoX socket is a for a regular session
2304  * or the special tunnel type.
2305  */
2306 static int pppol2tp_getsockopt(struct socket *sock, int level,
2307                                int optname, char __user *optval, int __user *optlen)
2308 {
2309         struct sock *sk = sock->sk;
2310         struct pppol2tp_session *session = sk->sk_user_data;
2311         struct pppol2tp_tunnel *tunnel;
2312         int val, len;
2313         int err;
2314
2315         if (level != SOL_PPPOL2TP)
2316                 return udp_prot.getsockopt(sk, level, optname, optval, optlen);
2317
2318         if (get_user(len, (int __user *) optlen))
2319                 return -EFAULT;
2320
2321         len = min_t(unsigned int, len, sizeof(int));
2322
2323         if (len < 0)
2324                 return -EINVAL;
2325
2326         err = -ENOTCONN;
2327         if (sk->sk_user_data == NULL)
2328                 goto end;
2329
2330         /* Get the session context */
2331         err = -EBADF;
2332         session = pppol2tp_sock_to_session(sk);
2333         if (session == NULL)
2334                 goto end;
2335
2336         /* Special case: if session_id == 0x0000, treat as operation on tunnel */
2337         if ((session->tunnel_addr.s_session == 0) &&
2338             (session->tunnel_addr.d_session == 0)) {
2339                 err = -EBADF;
2340                 tunnel = pppol2tp_sock_to_tunnel(session->tunnel_sock);
2341                 if (tunnel == NULL)
2342                         goto end_put_sess;
2343
2344                 err = pppol2tp_tunnel_getsockopt(sk, tunnel, optname, &val);
2345                 sock_put(session->tunnel_sock);
2346         } else
2347                 err = pppol2tp_session_getsockopt(sk, session, optname, &val);
2348
2349         err = -EFAULT;
2350         if (put_user(len, (int __user *) optlen))
2351                 goto end_put_sess;
2352
2353         if (copy_to_user((void __user *) optval, &val, len))
2354                 goto end_put_sess;
2355
2356         err = 0;
2357
2358 end_put_sess:
2359         sock_put(sk);
2360 end:
2361         return err;
2362 }
2363
2364 /*****************************************************************************
2365  * /proc filesystem for debug
2366  *****************************************************************************/
2367
2368 #ifdef CONFIG_PROC_FS
2369
2370 #include <linux/seq_file.h>
2371
2372 struct pppol2tp_seq_data {
2373         struct seq_net_private p;
2374         struct pppol2tp_tunnel *tunnel;         /* current tunnel */
2375         struct pppol2tp_session *session;       /* NULL means get first session in tunnel */
2376 };
2377
2378 static struct pppol2tp_session *next_session(struct pppol2tp_tunnel *tunnel, struct pppol2tp_session *curr)
2379 {
2380         struct pppol2tp_session *session = NULL;
2381         struct hlist_node *walk;
2382         int found = 0;
2383         int next = 0;
2384         int i;
2385
2386         read_lock_bh(&tunnel->hlist_lock);
2387         for (i = 0; i < PPPOL2TP_HASH_SIZE; i++) {
2388                 hlist_for_each_entry(session, walk, &tunnel->session_hlist[i], hlist) {
2389                         if (curr == NULL) {
2390                                 found = 1;
2391                                 goto out;
2392                         }
2393                         if (session == curr) {
2394                                 next = 1;
2395                                 continue;
2396                         }
2397                         if (next) {
2398                                 found = 1;
2399                                 goto out;
2400                         }
2401                 }
2402         }
2403 out:
2404         read_unlock_bh(&tunnel->hlist_lock);
2405         if (!found)
2406                 session = NULL;
2407
2408         return session;
2409 }
2410
2411 static struct pppol2tp_tunnel *next_tunnel(struct pppol2tp_net *pn,
2412                                            struct pppol2tp_tunnel *curr)
2413 {
2414         struct pppol2tp_tunnel *tunnel = NULL;
2415
2416         read_lock_bh(&pn->pppol2tp_tunnel_list_lock);
2417         if (list_is_last(&curr->list, &pn->pppol2tp_tunnel_list)) {
2418                 goto out;
2419         }
2420         tunnel = list_entry(curr->list.next, struct pppol2tp_tunnel, list);
2421 out:
2422         read_unlock_bh(&pn->pppol2tp_tunnel_list_lock);
2423
2424         return tunnel;
2425 }
2426
2427 static void *pppol2tp_seq_start(struct seq_file *m, loff_t *offs)
2428 {
2429         struct pppol2tp_seq_data *pd = SEQ_START_TOKEN;
2430         struct pppol2tp_net *pn;
2431         loff_t pos = *offs;
2432
2433         if (!pos)
2434                 goto out;
2435
2436         BUG_ON(m->private == NULL);
2437         pd = m->private;
2438         pn = pppol2tp_pernet(seq_file_net(m));
2439
2440         if (pd->tunnel == NULL) {
2441                 if (!list_empty(&pn->pppol2tp_tunnel_list))
2442                         pd->tunnel = list_entry(pn->pppol2tp_tunnel_list.next, struct pppol2tp_tunnel, list);
2443         } else {
2444                 pd->session = next_session(pd->tunnel, pd->session);
2445                 if (pd->session == NULL) {
2446                         pd->tunnel = next_tunnel(pn, pd->tunnel);
2447                 }
2448         }
2449
2450         /* NULL tunnel and session indicates end of list */
2451         if ((pd->tunnel == NULL) && (pd->session == NULL))
2452                 pd = NULL;
2453
2454 out:
2455         return pd;
2456 }
2457
2458 static void *pppol2tp_seq_next(struct seq_file *m, void *v, loff_t *pos)
2459 {
2460         (*pos)++;
2461         return NULL;
2462 }
2463
2464 static void pppol2tp_seq_stop(struct seq_file *p, void *v)
2465 {
2466         /* nothing to do */
2467 }
2468
2469 static void pppol2tp_seq_tunnel_show(struct seq_file *m, void *v)
2470 {
2471         struct pppol2tp_tunnel *tunnel = v;
2472
2473         seq_printf(m, "\nTUNNEL '%s', %c %d\n",
2474                    tunnel->name,
2475                    (tunnel == tunnel->sock->sk_user_data) ? 'Y':'N',
2476                    atomic_read(&tunnel->ref_count) - 1);
2477         seq_printf(m, " %08x %llu/%llu/%llu %llu/%llu/%llu\n",
2478                    tunnel->debug,
2479                    (unsigned long long)tunnel->stats.tx_packets,
2480                    (unsigned long long)tunnel->stats.tx_bytes,
2481                    (unsigned long long)tunnel->stats.tx_errors,
2482                    (unsigned long long)tunnel->stats.rx_packets,
2483                    (unsigned long long)tunnel->stats.rx_bytes,
2484                    (unsigned long long)tunnel->stats.rx_errors);
2485 }
2486
2487 static void pppol2tp_seq_session_show(struct seq_file *m, void *v)
2488 {
2489         struct pppol2tp_session *session = v;
2490
2491         seq_printf(m, "  SESSION '%s' %08X/%d %04X/%04X -> "
2492                    "%04X/%04X %d %c\n",
2493                    session->name,
2494                    ntohl(session->tunnel_addr.addr.sin_addr.s_addr),
2495                    ntohs(session->tunnel_addr.addr.sin_port),
2496                    session->tunnel_addr.s_tunnel,
2497                    session->tunnel_addr.s_session,
2498                    session->tunnel_addr.d_tunnel,
2499                    session->tunnel_addr.d_session,
2500                    session->sock->sk_state,
2501                    (session == session->sock->sk_user_data) ?
2502                    'Y' : 'N');
2503         seq_printf(m, "   %d/%d/%c/%c/%s %08x %u\n",
2504                    session->mtu, session->mru,
2505                    session->recv_seq ? 'R' : '-',
2506                    session->send_seq ? 'S' : '-',
2507                    session->lns_mode ? "LNS" : "LAC",
2508                    session->debug,
2509                    jiffies_to_msecs(session->reorder_timeout));
2510         seq_printf(m, "   %hu/%hu %llu/%llu/%llu %llu/%llu/%llu\n",
2511                    session->nr, session->ns,
2512                    (unsigned long long)session->stats.tx_packets,
2513                    (unsigned long long)session->stats.tx_bytes,
2514                    (unsigned long long)session->stats.tx_errors,
2515                    (unsigned long long)session->stats.rx_packets,
2516                    (unsigned long long)session->stats.rx_bytes,
2517                    (unsigned long long)session->stats.rx_errors);
2518 }
2519
2520 static int pppol2tp_seq_show(struct seq_file *m, void *v)
2521 {
2522         struct pppol2tp_seq_data *pd = v;
2523
2524         /* display header on line 1 */
2525         if (v == SEQ_START_TOKEN) {
2526                 seq_puts(m, "PPPoL2TP driver info, " PPPOL2TP_DRV_VERSION "\n");
2527                 seq_puts(m, "TUNNEL name, user-data-ok session-count\n");
2528                 seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
2529                 seq_puts(m, "  SESSION name, addr/port src-tid/sid "
2530                          "dest-tid/sid state user-data-ok\n");
2531                 seq_puts(m, "   mtu/mru/rcvseq/sendseq/lns debug reorderto\n");
2532                 seq_puts(m, "   nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
2533                 goto out;
2534         }
2535
2536         /* Show the tunnel or session context.
2537          */
2538         if (pd->session == NULL)
2539                 pppol2tp_seq_tunnel_show(m, pd->tunnel);
2540         else
2541                 pppol2tp_seq_session_show(m, pd->session);
2542
2543 out:
2544         return 0;
2545 }
2546
2547 static const struct seq_operations pppol2tp_seq_ops = {
2548         .start          = pppol2tp_seq_start,
2549         .next           = pppol2tp_seq_next,
2550         .stop           = pppol2tp_seq_stop,
2551         .show           = pppol2tp_seq_show,
2552 };
2553
2554 /* Called when our /proc file is opened. We allocate data for use when
2555  * iterating our tunnel / session contexts and store it in the private
2556  * data of the seq_file.
2557  */
2558 static int pppol2tp_proc_open(struct inode *inode, struct file *file)
2559 {
2560         return seq_open_net(inode, file, &pppol2tp_seq_ops,
2561                             sizeof(struct pppol2tp_seq_data));
2562 }
2563
2564 static const struct file_operations pppol2tp_proc_fops = {
2565         .owner          = THIS_MODULE,
2566         .open           = pppol2tp_proc_open,
2567         .read           = seq_read,
2568         .llseek         = seq_lseek,
2569         .release        = seq_release_net,
2570 };
2571
2572 #endif /* CONFIG_PROC_FS */
2573
2574 /*****************************************************************************
2575  * Init and cleanup
2576  *****************************************************************************/
2577
2578 static struct proto_ops pppol2tp_ops = {
2579         .family         = AF_PPPOX,
2580         .owner          = THIS_MODULE,
2581         .release        = pppol2tp_release,
2582         .bind           = sock_no_bind,
2583         .connect        = pppol2tp_connect,
2584         .socketpair     = sock_no_socketpair,
2585         .accept         = sock_no_accept,
2586         .getname        = pppol2tp_getname,
2587         .poll           = datagram_poll,
2588         .listen         = sock_no_listen,
2589         .shutdown       = sock_no_shutdown,
2590         .setsockopt     = pppol2tp_setsockopt,
2591         .getsockopt     = pppol2tp_getsockopt,
2592         .sendmsg        = pppol2tp_sendmsg,
2593         .recvmsg        = pppol2tp_recvmsg,
2594         .mmap           = sock_no_mmap,
2595         .ioctl          = pppox_ioctl,
2596 };
2597
2598 static struct pppox_proto pppol2tp_proto = {
2599         .create         = pppol2tp_create,
2600         .ioctl          = pppol2tp_ioctl
2601 };
2602
2603 static __net_init int pppol2tp_init_net(struct net *net)
2604 {
2605         struct pppol2tp_net *pn;
2606         struct proc_dir_entry *pde;
2607         int err;
2608
2609         pn = kzalloc(sizeof(*pn), GFP_KERNEL);
2610         if (!pn)
2611                 return -ENOMEM;
2612
2613         INIT_LIST_HEAD(&pn->pppol2tp_tunnel_list);
2614         rwlock_init(&pn->pppol2tp_tunnel_list_lock);
2615
2616         err = net_assign_generic(net, pppol2tp_net_id, pn);
2617         if (err)
2618                 goto out;
2619
2620         pde = proc_net_fops_create(net, "pppol2tp", S_IRUGO, &pppol2tp_proc_fops);
2621 #ifdef CONFIG_PROC_FS
2622         if (!pde) {
2623                 err = -ENOMEM;
2624                 goto out;
2625         }
2626 #endif
2627
2628         return 0;
2629
2630 out:
2631         kfree(pn);
2632         return err;
2633 }
2634
2635 static __net_exit void pppol2tp_exit_net(struct net *net)
2636 {
2637         struct pppoe_net *pn;
2638
2639         proc_net_remove(net, "pppol2tp");
2640         pn = net_generic(net, pppol2tp_net_id);
2641         /*
2642          * if someone has cached our net then
2643          * further net_generic call will return NULL
2644          */
2645         net_assign_generic(net, pppol2tp_net_id, NULL);
2646         kfree(pn);
2647 }
2648
2649 static struct pernet_operations pppol2tp_net_ops = {
2650         .init = pppol2tp_init_net,
2651         .exit = pppol2tp_exit_net,
2652 };
2653
2654 static int __init pppol2tp_init(void)
2655 {
2656         int err;
2657
2658         err = proto_register(&pppol2tp_sk_proto, 0);
2659         if (err)
2660                 goto out;
2661         err = register_pppox_proto(PX_PROTO_OL2TP, &pppol2tp_proto);
2662         if (err)
2663                 goto out_unregister_pppol2tp_proto;
2664
2665         err = register_pernet_gen_device(&pppol2tp_net_id, &pppol2tp_net_ops);
2666         if (err)
2667                 goto out_unregister_pppox_proto;
2668
2669         printk(KERN_INFO "PPPoL2TP kernel driver, %s\n",
2670                PPPOL2TP_DRV_VERSION);
2671
2672 out:
2673         return err;
2674 out_unregister_pppox_proto:
2675         unregister_pppox_proto(PX_PROTO_OL2TP);
2676 out_unregister_pppol2tp_proto:
2677         proto_unregister(&pppol2tp_sk_proto);
2678         goto out;
2679 }
2680
2681 static void __exit pppol2tp_exit(void)
2682 {
2683         unregister_pppox_proto(PX_PROTO_OL2TP);
2684         proto_unregister(&pppol2tp_sk_proto);
2685 }
2686
2687 module_init(pppol2tp_init);
2688 module_exit(pppol2tp_exit);
2689
2690 MODULE_AUTHOR("Martijn van Oosterhout <kleptog@svana.org>, "
2691               "James Chapman <jchapman@katalix.com>");
2692 MODULE_DESCRIPTION("PPP over L2TP over UDP");
2693 MODULE_LICENSE("GPL");
2694 MODULE_VERSION(PPPOL2TP_DRV_VERSION);